Phenotypic characterization and plasmidic pattern of multi-resistant Klebsiella pneumoniae in isolates from different hospitals in Medellín, Colombia

Abstract

Klebsiella spp, and in particular K. pneumoniae, is an important cause of nosocomial infection. In many occasions this microorganism is resistant to several antibiotics, including the new oxy-imino-cephalosporins, by means of extended-spectrum β-lactamase’s production (ESBL). Thirty-two isolates of K. pneumoniae, resistant to at least three different groups of antibiotics, were collected in four hospitals of high level complexity in Medellín (Colombia). The isolates were bio-typed, their susceptibility profile and production of β-lactamase of extended spectrum, as well as the plasmid band pattern determined. The biochemical identification and the susceptibility test were done in the Micro Scan system. The production  of  ESBL  was  done  using  the  QIAgen  micro-preparation  plasmid  kit,  and  evaluated  by  agarose  gel electrophoresis.

The results showed that nosocomial infection by K. pneumoniae is having a higher frequency in pediatric wards (48.8%, 14/32). The susceptibility test showed that all the isolates were resistant to piperacillin and ampicillin and susceptible to ciprofloxacin, ofloxacin, cefotetan and imipenem. The susceptibility to the other tested antibiotics was variable. Theisolates showed a susceptibility of 18.8% to the cephalosporins of third generation. Several new bio-types were identified, although 81% of the 32 analyzed isolates belonged to only three bio-types. A high percentage of isolates expressing ESBL was observed (65.6%). The plasmid band profile showed eight different patterns and one common band. These results show the necessity of increasing the regulations for the control and use of antibiotics, so the selective pressure of the intrahospital flora would be restricted.